Solid drawing compositions such as crayons, oil pastels, plastic crayons, colored pencils and the like generally comprise a wax, an extender pigment, a coloring pigment, a concentration adjuster, etc. Among these components, the extender pigment, concentration adjuster and the like may contain a predetermined amount of barium sulfate which enables the components to exhibit their functions effectively.
However, in recent years, standards for safety of toys have been altered in Europe and the U.S. to tighten control. Consequently pigments and like materials containing specific soluble heavy metals have been legally regulated. Since such heavy metals include barium, the use of barium lake and like pigments is restricted. The control is strict especially in Europe. For example, under European Standards EN 71, the detected value of barium as measured by the prescribed method shall not exceed 500 ppm.
At present, barium sulfate is not controlled under said regulation. However, the barium sulfate used as an extender pigment or as a concentration adjuster for a coloring pigment is slightly dissolved out so that a detected value of barium may exceed the prescribed level of 500 ppm, thereby posing a safety problem.
On the other hand, currently, no material is superior to barium sulfate as an additive for an extender pigment, concentration adjuster and the like, and it is difficult to find out a substitute for barium sulfate.